Wednesday, May 19, 2010

Image 1: This is an image of of a series circuit. There is one, equal current running through the whole circuit. The voltage remains the same throughout the whole series circuit. This is because there are no resistors, and in a series circuit, the voltage always remain the same.

Image 2: This is an image of a complex circuit. In this circuit, I have a parallel circuit, and a series circuit. The voltage is different in this circuit. The 1 light bulb in the series circuit is brighter than the 2 light bulbs in the parallel circuit because it has more voltage. The two light bulbs in the parallel circuit have the same voltage. The current in the parallel circuit is different to the current in the series circuit because it has more resistors.

Image 3: This image is of a parallel circuit. In this circuit, the voltage is the same between the two light bulbs. The current is the same in the parallel circuit. The current is equal to the voltage divided by the risistance. Since the voltage and resitance of both light bulbs are the same, the current is the same.

Monday, May 3, 2010

1. This is what i learned about optics. I learned that because of the law of reflection, the angle of incidence is equal to the angle of reflection. I learned how to draw the rays of the reflection's of the mirrors. I learned how to tell the difference between a virtual and real image, and i learned how to fin the image of an object by drawing rays. I learned all the different equations of mirrors, and i learned that if the distance of the image is +, then it is real (mirrors). Then i learned all about lenses. I learned how to draw the rays for lenses. Finally, i learned about total internal reflection. For incident angles greater than the critical angle, there is no refracted ray at all, causing total internal reflection.

2. What i have found difficult about optics is knowing how to draw the rays for all the different types of mirrors and lenses. For mirrors, there are convex, concave and flat. For lenses there are diverging and converging. For each of these, there are three rays. Luckily we only had to know 2! I got confused on all the different rays, and then got confused on how to tell which image was real or virtual.

3. My problem solving skills were the strongest they ever have been during this chapter. I was not intimidated at all by any long problems, and I always knew how to do them. I took them step by step, and solved them fully. The only thing i had a little trouble on was realizing whether and image was real or virtual, but i eventually learned how to tell the difference!

Sunday, April 25, 2010

The reason I chose to title this photo "Two birds with one stone," is because this is a similar situation. Two reflections with one photo! The first refection in this photo is the reflected image on the rifle scope. You can see the image of the window on the glass of the scope. If you look closely, you can tell that there are two images on the scope. They are both the same image, except the one on the left is upright, and the one on the left is inverted. The reason for this is because there are two lenses on a rifle scope. There is one at the beginning of the scope, and one at the end. The upright image is on the end lens of the scope. The image goes through the end glass, and reflects off the beginning glass. Then the image is reflected on to the other side of the back lens, making it inverted. The second reflection in he picture is the window reflecting an image on to the table, which we can see on the lens of the rifle. There is so much physics in just one photo!

Tuesday, March 23, 2010

The quote i chose was, "Its not that I'm so smart, it's just that i stay with problems longer." I really liked this quote because it goes to show that you don't have to be smart to solve difficult problems. If you stick with the problem long enough, you will be able to answer it. I also liked this because this is what i am working on with my problems, being able to stick with them long enough so i am able to get a precise answer instead of giving up on them right after i read it. I think that being able to stick with problems long enough to where you can get a good answer is a huge part in being "smart." Smart doesn't mean getting everything right all the time, it means trying your hardest, and not giving up. Sticking with problems for a long time is for sure a huge part of being smart!

Tuesday, March 9, 2010

Sunday, February 21, 2010

A1) This is what i learned about energy. I learned that work is energy transferred by forces that cause displacements. I learned how to do energy flow diagrams and the bar charts that go with them. The bar charts show the transfer of energy from the initial energy to the final energy. I learned the equation for work which is W=Fx, and if F and x are not parallel but F is at the angle with respect to x, then W=Fx cos 0. The units for work is Joules (J). The equation for Kinetic Energy i s KE=1/2mv^2.
The equation for Potential energy is PE=mgh. The equation for elastic potential energy is PEe=1/2kx^2. Mechanical Energy is the sum of KE and all forms of potential energy, so ME=PE + KE. Something that i really understood the most though was the conservation of energy and how energy is never lost. Before we started to learn this, i had always thought about that, but never really got it. I understand it now thought that no matter what kind of energy is transfered, it always remains the same.

A2) What i have found difficult about energy is all of the different equations. There are many equations that have many similar things in each equation. For example, there are 3 equations that have PE in them. This confuses me a lot, but what helps me if just taking it slow and really understanding what each equation is saying. The most difficult thing for me thought is knowing which energy is present. I have had trouble lately determining which energy is present.

A3) My problem solving skills are a lot better in this chapter than they have been usually. I am more confident and I am taking my time on a lot of the problems. I am also breaking a lot of the problems down piece by piece which helps me a lot. These three questions have helped to solve problems easier: Is the object at a height, 2. Is the object in contact with a spring, and 3. Is a force applied through a distance. Once i figure out the equation I need to use, it seems so easy. Just plug in the numbers and solve for whatever is needed!

B1) Everywhere i look there is conservation of energy! Bungee jumping, driving up a hill, climbing stair, going down a water slide, or shooting a gun. When at the top of a ski hill, and you are about to ski down the hill without stopping, you have a potential energy. When you are half way down the hill, you still have a potential energy because you still have a part of the hill in front of you, but you also have Kinetic Energy because you are moving. It is cool to know that the Potential Energy you had at the top of the hill is equal to the Kinetic Energy plus the Potential Energy you have when half way down the hill!

Wednesday, January 27, 2010

A. This is what I learned about circular motion and gravitation. Uniform circular motion is the motion of an object in a circle with a constant or uniform speed. The speed going around a circle is defined as v= 2πR/T. The period (T), is the time to complete one full rotation or revolution and is given in seconds. The frequency is the number of rotation per unit time, this unit is called Hertz (Hz). If the object is changing directions, it is accelerating. In the circular motion, it is called centripetal acceleration. Centripetal means it is always pointed toward the center. The formula for centripetal acceleration is Ac= V^2/R (m/s^2). The inward force that keeps the object moving in a circle is called centripetal force. The equation for this is Fc= mv^2/r. When attached to a string, the highest point of the vertical circular turn is given by Ft + Fg= mv^2/r, while the lowest part is Ft - Fg= mv^2/r. The law of universal gravitation states that " Every object in the universe attracts every other object in the universe with a force that varies directly with the product of their masses and inversely with the square of the distance between the centers of the two masses." To find the force of gravitation, use the equation Fg= Gm1m2/r^2. To find the acceleration due to gravity (g), use the equation g=GM/r^2.

B. What I have found difficult about what I have studied is the Universal Gravitation. To me, the circular motion is pretty easy, but the Universal Gravitation is difficult. I have trouble with scientific notation in the problems, and i get confused what to substitute into the different equations. Usually there are a lot of masses and i don't know which to substitute in. I also have a little trouble the "mu", and seeing that i can substitute Fn for mg when Fn=Fg.

C. My problem solving skill are strong in the circular motion problems, but in the Universal Gravitational problems, i have had a little trouble. The scientific notation, is frustrating, and sometimes messes me up with all of the number. It is also very easy to mess up on your calculator. I have also trouble knowing what to substitute into the equations. I am also very confused with all of the big G's, small G's, big M's, and small M's.

Sunday, January 10, 2010

Part A
Q1. This is what i have learned about Newtons Second Law. I learned the equation: Ef=ma, which is very helpful. I learned that the acceleration of an object is proportional to the net force and inversely proportional to the mass of an object, and the direction of an object is the same as the direction of the acceleration. Newtons Second Law links the cause (force) and the effect (acceleration) in a definite way.

Q2. What i have found difficult about what i have studied is being able to break down the problem and draw a FBD. To me, once you have drawn a FBD correctly, it is very easy to solve a problem. But sometimes i have trouble drawing a correct FBD because there are so many parts to a problem and i get overwhelmed. I hope I can learn to draw more correct FBD'S.

Q3. My problem solving skills are weaker than they should be. Lately i have been doing better in my problem solving skills. A couple of weeks ago, i would see a difficult problem and just not even try it. I would just look at it. Lately i have been able to get through many problems by breaking them step by step. I find the tactic very easy and helpful. My strengths are the algebraic parts of the problems. Once the FBD is drown and i can gather all of the data, I am good at setting up the equation for the sum force and solving for the unknown variable.

Part B.
Q1. There are many ways you can use what we have learned in Newton's Second Law in real life situation. Sort of like the problem on our last test, if you needed to find out a certain tension to lift an object off of the ground, we know to find the tension now! If you needed to move something, we now can figure out to amount of force you would need to exert on the object. I hope I will be able to use what we learned in class during real life experiences!